Paper currency acceptors have become well known in these days of escalating prices. Their usage is commonly applied to vending machines and the like, which often require the deposit of money in amounts inconvenient to carry in coin. Since these units can accept money, it is desirable for these units to employ a device for the accumulation and storage of accepted bills so that extended periods of unattended currency collection is possible. Examples of such currency acceptors and storage units can be found in U.S. Pat. Nos. 4,884,671; 4,540,081; 4,011,931; 4,418,824; and 4,678,072.
The bill accumulating storage units illustrated in the aforementioned references suffer a number of disadvantages. The most common of these disadvantages is the design of the storage units in a manner which makes them an integral component of the currency accepting device. Consequently, those bill storage mechanisms cannot be retrofitted to other currency acceptors.
Furthermore, many of the prior designs employ extremely complex mechanisms to push the accepted bill from the bill passageway into the spring loaded storage section of the bill accumulator. Such devices are costly to manufacture and assemble and can require heightened maintenance, which further increase the cost of operation of these devices.
Other weaknesses of prior designs include the use of linear acting solenoids to motivate the bill pushing plates which must overcome the force of a spring loaded plate in the bill storage area. Since these solenoids are given a short pulse of power by the control circuitry to transfer the bill into the storage section from the bill pathway, there are no provisions for verifying that the solenoid and bill pusher have successfully traversed their full range of motion when pushing a bill into the storage section. This can become a particular problem when a number of bills have already accumulated in the storage section, thus causing the spring in the storage section to be at least partially compressed. In this condition, significantly higher effort is required from the solenoid to overcome that spring pressure when pushing subsequent bills into the storage area.
In other machines where a linear actuator is used, a spring is often used which is oriented opposite the actuation direction in order to return the bill pushing mechanism to a rest position out of the way of the bill accumulator inlet passageway. Here, again there are no provisions to verify that the actuator spring has fully returned the pusher mechanism to that rest position. Additionally, the orientation of the return spring opposite the actuation direction makes necessary the additional requirement that the solenoid exert even higher effort to overcome the return spring force when pushing a bill into storage section. This condition exacerbates the previously mentioned problem, requiring a larger and more costly solenoid to provide the elevated levels of effort necessary for operation.